POS1475-HPR THE MINIMALLY IMPORTANT DIFFERENCE AS THE INTERPRETABILITY OF EMOTIONAL HEALTH DOMAIN IN JAPANESE VERSION OF LupusPRO FOR SLE PATIENTS; PRELIMINARY RESULTS OF A PROSPECTIVE COHORT STUDY
Authors: Y. Miyawaki, K. Shidahara, S. Nawachi, Y. Asano, Y. Katayama, K. Ohashi, E. Katsuyama, T. Katsuyama, M. Narazaki, Y. Matsumoto, K. E. Sada, R. Yanai, N. Yajima, A. Takatani, K. Ichinose, J. Wada
Journal: Annals of the Rheumatic Diseases (2022)

Background The minimally important difference (MID) required to interpret the magnitude of changes in lupus patient-reported outcome (LupusPRO), which is a widely used outcome measure of quality of life in SLE patients, remains unclear. Objectives We report preliminary results of an ongoing prospective observational study that assesses the MID as the interpretability of emotional health (EH) domain in Japanese version of LupusPRO. Methods We recruited subjects at three university hospitals in Japan participating in an ongoing multidisciplinary cohort study (the Lupus registry of Nationwide institutions (LUNA). Of a total of 210 SLE patients enrolled during the 17-month recruitment period, patients with low disease activity, defined as SLE Disease Activity Index 2000 (SLEDAI-2K) ≤ 4, and who were seen at least twice of three months’ duration and responded to both the LupusPRO and health status change questions were included in this subcohort. The second questionnaire was given an allowance period of 30 days before or after the ​three months from starting date. Descriptive statistics were presented as means and standard deviations (SD) or counts and percentages (%). The emotional health score ranges from 0 to 100; a higher score indicates less frequent presence of symptoms. The change in health status was assessed using the 7-point Global Rating of Change 1) , and the score = 0 and the score ≥ +1 were considered in the ‘unchanged’ and the minimal ‘improved’ category, respectively. MID was mainly estimated using the mean change of the groups with the score ≥ +1 as the anchor-based method, and the area under the curve (AUC) was also calculated as a sensitivity analysis to estimate MID thresholds 2) and 95% confidence intervals (CI) were constructed using 1000 bootstrapping. Results The mean age of the 24 eligible patients was 48 (SD 14), and 88% were female. The glucocorticoid dose, SLEDAI-2K, and Systemic Lupus International Collaborating Clinics /American College of Rheumatology Damage Index were 3.4 (2.1) mg, 1.0 (1.1) and 1.1 (1.9), respectively. The mean EH score was 67.5 (30.3), five patients (21%) had the maximum EH score at baseline, 73.4 (25.0) after three months, 7.2 (18.0) for the change in EH. The correlation coefficient and the AUC for the change in health status and the EH were 0.23 and 0.60. The mean changes were 4.1 (18.4) of the groups with ‘unchanged’ health status and 12.3 (17.1) of the groups with ‘improved’ health status. The MID for improvement was estimated at 12.3 using the anchor-based method, and the cutoff point corresponded to 9.3 [95%CI -6.7 to 25.3]) of the EH change score by the receiver operating curve method. Conclusion In this study, the MID (3 months) for the EH domain in the Japanese version of LupusPRO was estimated to be between 9 and 12, which was similar to the results of the previous cross-sectional study 3) . The challenge in estimating the MID in our setting was the low correlation with external anchors, even though the study population was limited to patients with low disease activity, because disease activity at baseline can generally influence ‘improved’ health status. References [1]Kamper SJ, Maher CG, Mackay G. Global rating of change scales: a review of strengths and weaknesses and considerations for design. J Man Manip Ther. 2009;17(3):163. [2]Froud R, Abel G. Using ROC curves to choose minimally important change thresholds when sensitivity and specificity are valued equally: the forgotten lesson of pythagoras. theoretical considerations and an example application of change in health status. PLoS One. 2014;9(12):e114468. [3]Miyawaki Y, Shimizu S, Ogawa Y, et al. Association of glucocorticoid doses and emotional health in lupus low disease activity state (LLDAS): a cross-sectional study. Arthritis Res Ther. 2021;23(1):79. Acknowledgements The authors thank Yuka Nakanou for her significant assistance in data management and Kikuko Miyazaki for her expert assistance on this topic. Disclosure of Interests Yoshia Miyawaki: None declared, Kenta Shidahara: None declared, Shoichi Nawachi: None declared, Yosuke ASANO: None declared, Yu Katayama: None declared, Keiji Ohashi: None declared, Eri Katsuyama: None declared, Takayuki Katsuyama: None declared, Mariko Narazaki: None declared, Yoshinori Matsumoto Speakers bureau: I received speaker’s fees from Glaxo Smith Kline K.K., KEN-EI SADA Speakers bureau: I received speaker’s fees from Glaxo Smith Kline K.K., Ryo Yanai: None declared, Nobuyuki Yajima: None declared, Ayuko Takatani: None declared, Kunihiro Ichinose: None declared, Jun Wada Speakers bureau: Jun Wada receives speaker honoraria from Astra Zeneca, Daiichi Sankyo, Novartis, Novo Nordisk Pharma, Tanabe Mitsubishi and receives grant support from Astellas, Baxter, Bayer, Chugai, Dainippon Sumitomo, Kyowa Kirin, Novo Nordisk Pharma, Ono, Otsuka, Tanabe Mitsubishi, and Teijin.